Drill chucks are known which include a friction brake, consisting of, for example, an elastic O-ring which is disposed between respective cylindrical surfaces of the chuck bushing and the internal chuck members. The known friction device has the disadvantage that intentional opening of the chuck is impeded during the entire opening process. For this reason, the frictional forces must be kept relatively weak which diminishes the effectiveness of the known device to accomplish its purpose, i.e., to prevent the unintentional opening of the drill chuck.